When a jet-powered aircraft lands, the landing gear brakes and aerodynamic drag (e.g., flaps, spoilers, etc.) of the aircraft may not, in certain situations, be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the braking of the aircraft. When deployed, a thrust reverser redirects the rearward thrust of the jet engine to a generally or partially forward direction to decelerate the aircraft. Because at least some of the jet thrust is directed forward, the jet thrust also slows down the aircraft upon landing.
Various thrust reverser designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Thrust reverser designs used most prominently with jet engines fall into three general categories: (1) cascade-type thrust reversers; (2) target-type thrust reversers; and (3) pivot door thrust reversers. Each of these designs employs a different type of moveable thrust reverser component to change the direction of the jet thrust.
Cascade-type thrust reversers are can be used on high-bypass ratio jet engines. This type of thrust reverser is located on the circumference of the engine's midsection and, when deployed, exposes and redirects air flow through a plurality of cascade vanes. The moveable thrust reverser components in the cascade design includes several translating sleeves or cowls (“transcowls”) that are deployed to expose the cascade vanes.
Target-type reversers, also referred to as clamshell reversers, are typically used with low-bypass ratio jet engines. Target-type thrust reversers use two doors as the moveable thrust reverser components to block the entire jet thrust coming from the rear of the engine. These doors are mounted on the aft portion of the engine and may form the rear part of the engine nacelle.
Pivot door thrust reversers may utilize four doors on the engine nacelle as the moveable thrust reverser components. In the deployed position, these doors extend outwardly from the nacelle to redirect the jet thrust.
The primary use of thrust reversers is, as noted above, to enhance the braking of the aircraft, thereby shortening the stopping distance during landing. Hence, thrust reversers are usually deployed during the landing process to slow the aircraft. Thereafter, when the thrust reversers are no longer needed, they are returned to their original, or stowed, position. Once in the stowed position, the one or more locks are engaged to prevent unintended movement of the thrust reversers and/or actuators that move the thrust reversers.
In the past, many of the above described thrust reverser systems were hydraulic-type systems, and included various hydraulically operated actuation and control devices. Although safe and reliable, many hydraulic systems and components have exhibited small amounts of leakage, resulting in the need for periodic clean up. Hence, in an effort to do away with at least some of the hydraulic systems and components on aircraft, thrust reverser actuation systems are being designed and implemented using electrically operated and controlled components. These electrically operated components include various motors and solenoids, which are used to control the various thrust reverser system actuators and locks.
Although electrical thrust reverser actuation systems are safe, reliable, and robustly designed, these systems also exhibit certain drawbacks. For example, some of the locks may need relatively large solenoids or dedicated electric motors to ensure proper operation. These large solenoids and dedicated motors can increase overall system size envelope, and overall system weight, both of which can lead to increased implementation costs.
Hence, there is a need for a system and method of controlling thrust reverser actuation system locks in an electrical thrust reverser actuation system that does not rely on relatively large solenoids and/or dedicated motors and/or does not increase overall system size and/or does not increase overall system weight and/or does not increase system implementation costs. The present invention addresses one or more of these needs.